In a furious exchange with the Obama administration over the mid-August ruling, Canada has launched its own investigation and will soon close its skies to U.S. sports team charters in retaliation, warns Transport Minister John Baird.

The sticking point is an eight-year-old exemption that had allowed sports and celebrity charters to make several pit stops in American cities. Under existing open skies agreements, regular Canadian airline flights can only visit one U.S. city before returning. NHL Deputy Commissioner Bill Daly warns the charter ban will create a complicated « patchwork » of travel that could « wreck havoc » with the oncoming hockey schedule, including early league games in Europe, as teams scramble to book flights under the new rules.